Pressure responsive switch assembly

Abstract

A vacuum operable, snap-action assembly utilizing a metal disc and flexible diaphragm structure to move a switch between first and second positions is disclosed. The switch and disc assembly are provided in a protective housing and are responsive to a pressure differential across the disc and diaphragm structure.

I claim: 
     
       1. A pressure responsive switch assembly comprising: a housing defining an enclosure, a vacuum port and a reference port;   diaphragm-actuator means mounted in said enclosure and cooperating with said housing to define a reference chamber and an actuation chamber;   a source of fluid at a reference pressure communicating with said reference chamber through said reference port;   a source of fluid at a variable vacuum communicating with said actuation chamber through said vacuum port;   disc-shaped means disposed in said actuation chamber separate from but adjacent to said diaphragm-actuator means for maintaining said diaphragm-actuator means at a reference position when said disc-shaped means assumes a first position, said disc-shaped means being deformable to a second position by said diaphragm-actuator means in response to a predeteremined first fluid differential pressure between said actuation chamber and said reference chamber and being reformable to said first position at a second fluid pressure differential less than said first fluid pressure differential; and   operative switch means disposed in said reference chamber as an assembly which is responsive to position changes of but is independently mounted from said diaphragm-actuator means and disc-shaped means and which is protected from variable vacuum fluid contamination by said diaphragm actuator means.   
     
     
       2. The invention according to claim 1 wherein said switch assembly means includes terminals extending through said housing. 
     
     
       3. The invention according to claim 1 wherein said disc-shaped means is formed from a phosphorous-bronze material. 
     
     
       4. The invention according to claim 1 wherein said switch assembly is an on-off switch. 
     
     
       5. The invention according to claim 1 wherein said switch assembly means operates between normally open and normally closed positions. 
     
     
       6. The invention according to claim 1 wherein said vacuum port includes an orifice positioned therein to provide a controlled flow between said source of fluid from a variable vacuum and said actuation chamber.